Biopsy needle with integrated guide pin

1. A biopsy instrument for use in a biopsy gun, comprising:

a hollow outer needle having a proximal end and a distal end and defining a lumen therethrough;

an inner needle slidably disposed within said lumen, said inner needle having a proximal end and a distal end and defining a cavity adjacent said distal end for receiving a tissue sample;

said inner and outer needles slideable relative to one another between a first position wherein said distal end of said inner needle is retracted within said lumen so that said outer needle covers said cavity and a second position wherein said distal end of said inner needle is extended away from said outer needle to expose said cavity;

a first hub attached to said proximal end of said inner needle;

a second hub attached to said proximal end of said outer needle, said second hub having a track running parallel to said outer needle and a stop member projecting from a surface of said second hub adjacent said track, wherein said track is defined by said surface, a wall projecting from said surface and a dog projecting from said wall; and

an elongated pin having a first end, a second end and an arm projecting from said second end, said first end fixedly attached to said first hub with said shaft parallel to said inner needle and said pin slidingly engaged to said second hub within said track, said second hub slideable along said pin between a location near said first end and said second end where said arm meets said stop member.

2. The biopsy instrument of claim 1 wherein said second hub is slideable along said pin a distance sufficient to enable operation of the biopsy instrument in a biopsy gun.

3. The biopsy instrument of claim 1 wherein said second hub is slideable along said pin a predetermined distance to enable insertion of said biopsy needle in a biopsy gun.

4. The biopsy instrument of claim 1 further comprising a ramp projecting from said surface at a location distal to said stop member, said ramp inclined towards said stop member.

5. The biopsy instrument of claim 4 wherein said ramp includes a ramp head facing said stop member, said ramp head and said stop member defining a space, said space having a length that is at least as large a cross sectional dimension of said arm.

6. The biopsy instrument of claim 5 wherein said ramp has a height sufficient to prevent said arm from backing over said ramp as the biopsy instrument is inserted into the biopsy gun when said arm is positioned in said space.

7. The biopsy instrument of claim 6 wherein said ramp has a height of at least about one third of a height of said arm.

8. The biopsy instrument of claim 6 wherein said ramp has a height sufficient to provide a tactile indication when said arm slides over ramp and into said space.

9. The biopsy instrument of claim 6 wherein said track is defined by said surface, a wall projecting from said surface and a dog projecting from said wall.

10. A biopsy instrument for use in a biopsy gun, comprising:

a hollow outer needle having a proximal end and a distal end and defining a lumen therethrough;

an inner needle slidably disposed within said lumen, said inner needle having a proximal end and a distal end;

a first hub attached to said maximal end of said inner needle;

a second hub attached to said proximal end of said outer needle;

an elongated pin having a first end and a second end, said first end fixedly attached to said first hub and said pin in sliding contact with said second hub so that said second hub is moveable relative to said pin between said first end and said second thereof, said elongated pin including an engagement member at said second end configured to engage said second hub when said second hub is at said second end; and

a ramp projecting from a surface at a location distal to stop member, said ramp inclined towards said stop member.

11. The biopsy instrument of claim 10 wherein one of said first and second hubs is slideable relative to the other of said first and second hubs to a position wherein a distance between said first hub and said second hub is sufficient to enable operation of the biopsy instrument in a biopsy gun.

12. The biopsy instrument of claim 10 wherein one of said first and second hubs is slideable relative to the other of said first and second hubs to a position wherein a distance between said first hub and said second hub a predetermined distance to enable insertion of said biopsy needle in a biopsy gun.

13. The biopsy instrument of claim 10 wherein said engagement member is an arm projecting from said second end of said pin.

14. The biopsy instrument of claim 13 wherein said engagement member engages said second hub at a stop member projecting from a surface of said second hub.

15. The biopsy instrument of claim 14 , wherein said second hub defines a track running parallel to said outer needle and said pin is slideable within said track.

16. The biopsy instrument of claim 15 wherein said stop member is adjacent said track.

17. The biopsy instrument of claim 10 wherein said ramp includes a ramp head facing said stop member, said ramp head and said stop member defining a space, said space having a length that is at least as large as a cross sectional dimension of said arm.

18. The biopsy instrument of claim 17 wherein said ramp has a height sufficient to prevent said arm from backing over said ramp as the biopsy instrument is inserted into the biopsy gun when said arm is positioned in said space.

19. The biopsy instrument of claim 18 wherein said ramp has a height of at least about one third of a height of said arm.

20. The biopsy instrument of claim 18 wherein said ramp has a height sufficient to provide a tactile indication when said arm slides over ramp and into said space.

21. The biopsy instrument of claim 18 wherein said track is defined by said surface, a wall projecting from said surface and a dog projecting from said wall.

22. The biopsy instrument of claim 21 wherein said first hub defines a longitudinal bore said first end of said pin is fixedly attached within said longitudinal bore, said longitudinal bore, said track and said dog cooperating to prevent rotational movement of said hubs relative to each other.